Application of Carbon-13 Isotopomer Analysis to Assess Perinatal Myocardial Glucose Metabolism in Sheep.

Mukundan Ragavan,Mengchen Li,Anthony G Giacalone,Charles E Wood,Matthew E Merritt,Maureen Keller-Wood

doi:10.3390/metabo11010033

Application of Carbon-13 Isotopomer Analysis to Assess Perinatal Myocardial Glucose Metabolism in Sheep.

Mukundan Ragavan, Mengchen Li + Show 4 more

Open Access

https://doi.org/10.3390/metabo11010033

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Journal: Metabolites	Publication Date: Jan 5, 2021
Citations: 2	License type: CC BY 4.0

Affiliation: University of Florida

Abstract

Ovine models of pregnancy have been used extensively to study maternal–fetal interactions and have provided considerable insight into nutrient transfer to the fetus. Ovine models have also been utilized to study congenital heart diseases. In this work, we demonstrate a comprehensive assessment of heart function and metabolism using a perinatal model of heart function with the addition of a [U-13C]glucose as tracer to study central energy metabolism. Using nuclear magnetic resonance spectroscopy, and metabolic modelling, we estimate myocardial citric acid cycle turnover (normalized for oxygen consumption), substrate selection, and anaplerotic fluxes. This methodology can be applied to studying acute and chronic effects of hormonal signaling in future studies.

Highlights

The myocardium undergoes a transition from utilizing carbohydrates as the primary energy source during the perinatal period to using fatty acids preferentially as an adult [1,2]
Carbon-13 nuclear magnetic resonance (NMR) has excellent chemical selectivity and has been used to measure fluxes in pathways involved in central energy metabolism in perfused hearts [6,7,8], and livers [9,10]
We have demonstrated the use of carbon-13 isotopomer analysis to directly study glucose metabolism in fetal sheep hearts

Summary

Introduction

The myocardium undergoes a transition from utilizing carbohydrates as the primary energy source during the perinatal period to using fatty acids preferentially as an adult [1,2]. Carbon-13 NMR has excellent chemical selectivity and has been used to measure fluxes in pathways involved in central energy metabolism in perfused hearts [6,7,8], and livers [9,10]. Ovine models of pregnancy have been previously used to study arterial-venous (A-V) differences in oxygen and glucose across the fetal heart [12]. These measurements have been made in hypoxic conditions using the same models [13]. Insightful, these studies do not provide granular information on substrate selection or fluxes through pathways involved in energy metabolism. By infusing 13C enriched glucose and measuring oxygen consumed by the heart, we estimate citric acid cycle (TCA cycle) flux, and substrate selection in the fetal heart

Results

Animal Use

Extraction of Metabolites

NMR Spectra Acquisition

Steady State Analysis